Pop-up irrigation sprinklers are typically buried in the ground and include a stationary housing and a riser assembly, mounted within the housing, that cycles up and down during an irrigation cycle. During an irrigation cycle, the riser assembly is propelled through an open upper end of the housing and projects above ground level, or “pops up,” to distribute water to surrounding terrain. More specifically, pressurized water is supplied to the sprinkler through a water supply line attached to an inlet of the housing. The pressurized water causes the riser assembly to travel upwards against the bias of a spring to the elevated spraying position above the sprinkler housing to distribute water to surrounding terrain through one or more spray nozzles. When the irrigation cycle is completed, the pressurized water supply is shut off and the riser is spring-retracted back into the sprinkler housing so that the housing and riser assembly are again at and below ground level.
A rotary sprinkler commonly includes a rotatable turret mounted at the upper end of the riser assembly. The turret includes one or more spray nozzles for distributing water and is rotated through an adjustable arcuate water distribution pattern.
Rotary sprinklers commonly include a water-driven motor to transfer energy of the incoming water into a source of power to rotate the turret. One common mechanism uses a water-driven turbine and a gear reduction system to convert the high speed rotation of the turbine into relatively low speed turret rotation. Some examples of rotary sprinklers include the sprinklers described in U.S. Pat. Nos. 4,625,914; 4,787,558; 5,383,600; 6,732,950; and 6,929,194; all assigned to the assignee of this application, Rain Bird Corporation.
During normal operation, the turret rotates to distribute water outwardly over surrounding terrain in an arcuate pattern. Rotary sprinklers commonly employ an arc adjustment mechanism, accessible from the top of the turret, to adjust the arcuate range of the turret. The arc adjustment member typically is a screw or shaft with a slotted first end manually adjustable by a tool, such as a screwdriver, to set end limits of rotation for the turret. In one example, as described in U.S. Pat. No. 5,383,600, the arc adjustment member is used to change the relative arcuate distance between two trip stops that define the limits of rotation for the turret. One trip stop is fixed with respect to the turret while the second trip stop, operatively coupled to the second end of the adjustment screw, can be selectively moved arcuately relative to the turret to increase or decrease the desired arc of coverage.
During the course of normal operation, sand particles, grit, and other debris tend to accumulate in, and become trapped in, the tool-engaging slot of the arc adjustment member. After a certain amount of accumulation, the slot of the arc adjustment member becomes too clogged with such debris so as to prevent engagement with an appropriate hand tool. Attempts to engage the clogged slot with the hand tool often result in disintegration of the head of the arc adjustment member. The end result is that the arc adjustment member ceases to function, and the user can no longer adjust the water distribution arc of the sprinkler. It has been estimated that 70% to 80% of arc adjustment failures are due to the arc adjustment slot becoming damaged or otherwise failing to function in this manner.
Accordingly, a need exists to periodically flush the slot of the arc adjustment member to minimize the accumulation of sand particles, grit, and other debris. There is a need for a self-flushing mechanism that prevents damage to the slot and failure of the arc adjustment member. Further, there is a need to flush the slot in a manner that does not result in the unduly wasteful use of water. In addition, there is a need to flush other adjustment members and other areas of the interior of the turret that are prone to accumulation of grit and other debris.